Backward compatible SWAPN, DUPN, EXCHANGE

The five-minute read

One action, walked through

1. Open EIP 8024 and read the status line before the examples.
2. Write down the rule in one sentence. A fair version of that sentence is: Currently, SWAP and DUP instructions are limited to a stack depth of 16.
3. Name the object that changes: SWAP, DUP, SWAPN.
4. Ask what an old client, an old contract, or an offline counterparty does. If the document is silent, the silence is part of the design.

The argument, unpacked

What has to be true

• You are implementing EIP 8024 at the status the text itself states: Review.
• The object that has to change is SWAP, DUP, SWAPN. A neighbouring document with a similar name is not this one.
• Constants in the text can be superseded by a later fork. Cite the EIP number and the fork you mean.

What happened after the paper

The source marks this review. It is not a live consensus rule just because it has a number. Later documents can narrow, replace, or ignore this one. Cite the number you mean.

What to check before you use the idea

• What does Backward compatible SWAPN, DUPN, EXCHANGE charge, reject, or redefine on the first touch versus a later one?
• Does a reverted subcall roll the change back?
• Can you point at the object in a client: SWAP, DUP, SWAPN?

Terms

EIP 8024

The public text titled Backward compatible SWAPN, DUPN, EXCHANGE.

Review

The document's own label for how finished the text is. It is not a market fact.

The problem the paper names

An underpriced or ambiguous EVM rule is not a feature. It is a block that takes longer than the gas limit claimed, or a client that disagrees about the result.

What the design proposes

• Currently, SWAP and DUP instructions are limited to a stack depth of 16.
• Introduce three new instructions, SWAPN, DUPN and EXCHANGE which lift this limitation and allow accessing the stack at higher depths.
• While the stack is 1024 items deep, easy access is only possible for the top 16 items.

How the mechanism is specified

• Taken from the specification, the next constraint is: Introduce three new instructions, SWAPN, DUPN and EXCHANGE which lift this limitation and allow accessing the stack at higher depths.
• Locate SWAP, DUP, SWAPN in EIP 8024 and apply it to one transaction or call.
• Then check the failure the class of rule always has: a node that did not upgrade, a reverted call, a replayed signature, or a peer that does not speak the message.

What this page does not treat as proven

• A gas or opcode change is not a throughput benchmark. It is a relative price and a validity rule.
• Constants in the text can be superseded by a later fork. Cite the EIP number and the fork you mean.
• The source marks this review. It is not a live consensus rule just because it has a number.

Why a venture studio still reads it

Use EIP 8024 when a pitch says 'Backward compatible SWAPN, DUPN, EXCHANGE' without saying whether the rule is consensus, policy, or an interface. The number is the citation. The pitch is not.